ICallbackHandler.HandleCallbacks(ICallback[]) Method

Definition

Namespace:

Javax.Security.Auth.Callback

Assembly:

Mono.Android.dll

Retrieve or display the information requested in the provided Callbacks.

[Android.Runtime.Register("handle", "([Ljavax/security/auth/callback/Callback;)V", "GetHandleCallbacks_arrayLjavax_security_auth_callback_Callback_Handler:Javax.Security.Auth.Callback.ICallbackHandlerInvoker, Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null")]
public void HandleCallbacks (Javax.Security.Auth.Callback.ICallback[]? callbacks);

[<Android.Runtime.Register("handle", "([Ljavax/security/auth/callback/Callback;)V", "GetHandleCallbacks_arrayLjavax_security_auth_callback_Callback_Handler:Javax.Security.Auth.Callback.ICallbackHandlerInvoker, Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null")>]
abstract member HandleCallbacks : Javax.Security.Auth.Callback.ICallback[] -> unit

Parameters

callbacks

ICallback[]

an array of Callback objects provided by an underlying security service which contains the information requested to be retrieved or displayed.

Attributes

RegisterAttribute

Exceptions

IOException

if an I/O related error occurs

UnsupportedCallbackException

if the CallbackHandler is not able to handle a specific Callback

Remarks

Retrieve or display the information requested in the provided Callbacks.

The handle method implementation checks the instance(s) of the Callback object(s) passed in to retrieve or display the requested information. The following example is provided to help demonstrate what an handle method implementation might look like. This example code is for guidance only. Many details, including proper error handling, are left out for simplicity.

{@code
            public void handle(Callback[] callbacks)
            throws IOException, UnsupportedCallbackException {

              for (int i = 0; i < callbacks.length; i++) {
                 if (callbacks[i] instanceof TextOutputCallback) {

                     // display the message according to the specified type
                     TextOutputCallback toc = (TextOutputCallback)callbacks[i];
                     switch (toc.getMessageType()) {
                     case TextOutputCallback.INFORMATION:
                         System.out.println(toc.getMessage());
                         break;
                     case TextOutputCallback.ERROR:
                         System.out.println("ERROR: " + toc.getMessage());
                         break;
                     case TextOutputCallback.WARNING:
                         System.out.println("WARNING: " + toc.getMessage());
                         break;
                     default:
                         throw new IOException("Unsupported message type: " +
                                             toc.getMessageType());
                     }

                 } else if (callbacks[i] instanceof NameCallback) {

                     // prompt the user for a username
                     NameCallback nc = (NameCallback)callbacks[i];

                     // ignore the provided defaultName
                     System.err.print(nc.getPrompt());
                     System.err.flush();
                     nc.setName((new BufferedReader
                             (new InputStreamReader(System.in))).readLine());

                 } else if (callbacks[i] instanceof PasswordCallback) {

                     // prompt the user for sensitive information
                     PasswordCallback pc = (PasswordCallback)callbacks[i];
                     System.err.print(pc.getPrompt());
                     System.err.flush();
                     pc.setPassword(readPassword(System.in));

                 } else {
                     throw new UnsupportedCallbackException
                             (callbacks[i], "Unrecognized Callback");
                 }
              }
            }

            // Reads user password from given input stream.
            private char[] readPassword(InputStream in) throws IOException {
               // insert code to read a user password from the input stream
            }
            }

Java documentation for javax.security.auth.callback.CallbackHandler.handle(javax.security.auth.callback.Callback[]).

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.